All over the world, coastal populations depend on, and influence, the environment in pursue of their livelihoods. Managing the environment, while meeting the growing demand for marine resources, is a challenge. It further requires knowledge about all actors. Women's contribution is often overlooked in research, policy and management of marine and coastal resources. This thesis aims to reduce this gap; a gender analysis is applied to differentiate women and men's access and use of the seascape and to address key gender issues in coastal livelihoods in Zanzibar, Tanzania. Paper I shows that men are typically engaged in fisheries and have access to the whole seascape, whereas women engage in less economically viable activities, such as seaweed farming and invertebrate harvesting, in near-shore areas. A limitation for women to reach the whole seascape is a general lack of boat transport, swimming skills and fishing gear. Paper II analyzes occupational health within seaweed farming and shows that women seaweed farmers suffer from a variety of problems, such as eye infections, musculoskeletal pains, respiratory problems and fatigue, because of poor working conditions. Paper III addresses social and ecological aspects of invertebrate harvesting. This activity lacks proper management and over a five-year period (2005 to 2010), invertebrate abundance and species richness have decreased. It also reveals gender disparities in access to invertebrate collecting grounds and species of higher economic value. Paper IV examines gender within fish trade; women traders have less access to markets, high-value fish, a diverse customer-base, cold-storing facilities and fish trade associations. Income data shows that women's income is always lower. The management system is found to be androcentric and this thesis thus argues for the need to look at the "bigger picture"; the whole seascape, both men and women, and their interests should be considered in coastal and marine management.